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In the ValueSet resource any number of terms ('designations 
') in additional languages and dialects can be specified for a particular concept in a value set definition using the ValueSet.compose.include.concept.designation element. The language is specified as a BCP-47 language code as required by the 'designation.language ' element, with the value taken from the 'languageCode' field of the RF2 Descriptions file ('languageCode' is ISO-639-1, a subset of BCP-47). BCP-47 private use extensions can be used to specify the a SNOMED CT language reference set of for a term. The form for format of these extensions is <lang>-x-sctlang-<language reference set ID>, for example en-x-sctlang-90000000-00005090-07 corresponds to the US English language reference set. The SNOMED CT Expression Constraint Language specification also lists a number of aliases for language reference sets which may be used: Dialect Aliases. The type of the term (e.g., the SNOMED CT code for "Fully specified name", "Synonym" or "Definition") can be specified in 'designation.use '.
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